Insecticida



Reissued Feb. 13, 1951 UNITED STATES PATENT OFFICE Herman Wachs,Brooklyn, N. Y., assignor, by

mesne assignments, to U. "S. Industrial Chemicals, Inc., New York, N.Y., a corporation of Delaware No Drawing. Original No. 2,457,957, datedJanuary 4, 1949, SerialNo. 657,064, March 25, 1946. Application forreissue November 3,1950, Serial 4 Claims.

This invention relates to new insecticidal compositionsandmore'particularly to such compositions comprising mixtures ofpyrethrins and the methylene ether of 3.4oxymethylene-phenyl-lbutylglycol.

The methylene ether of 3.4 oxymethylenephenyl-l-butylglycol is a knownproduct and is readily-prepared by the condensation of isosafrol andformaldehyde according to the directions given by H. J. Prins inChemische Weekblad, volume 16, pages 1523-1524 (1919).

I have found that the methylene ether of 3.4oxymethylene-phenyl-l-butylglycol is a valuable synergist for use withpyrethrins. Thus a solution of 30 mg. of pyrethrins and 300 mg. of themethylene ether in 100 c. c. of petroleum base oil (containing asecondary solvent), when tested in the Feet Grady chamber, showed 100%knockdown and 85% kill (0. T. I. kill 46). The synergistic action of themethylene ether is indicated by the fact that a solution containing 30mg. of pyrethrins in 100 c. c. of petroleum base oil showed apractically negligible kill and a solution of 300 mg. of the methyleneether in 100 c. c. of base oil also showed a practically negligible killwhen tested according to the Peet Grady method. The combination of themethylene ether with the pyrethrins, however, showed 85% kill.

The methylene ether itself is insoluble in base oil but can be readilydissolved when a secondary solvent is used. In preparing the solutioncontaining 30 mg. of pyrethrins and 300 mg. of the ether in 100 c. c. ofbase oil, a secondary solvent is also used. Only very small amounts ofthe secondary solvent are needed. Among the secondary solvents which canbe so used are iso-- propanol, butyl Carbitol (the butyl ether ofdiethylene glycol), butyl Cellosolve (the butyl ether of ethyleneglycol), velsicol solvents (aromatic closed-chain solvents of petroleumorigin) and betachloro-beta-thymoxy-diethyl ether.

The proportions of pyrethrins and methylene ether can be varied over awide range. Instead of using a ratio of 30 mg. of pyrethrins to 300 mg.of the methylene ether per 100 c. c. of petroleum base oil, aninsecticidal spray composition of similar activity may be produced byusing as little as 5 mg. of pyrethrins per 100 c. c. of petroleum baseoil, but in this case the quantity of the methylene ether should beincreased to around 1 g.

Matter enclosed in heavy brackets appears in the original patent butforms no part of this reissue specification; matter printed in italicsindicates the additions made by reissue These proportions given by wayof illustration may be varied over a wide range. Thus, a highlyeflicient household spray may be prepared ac-.- cording to the presentexample.

1 c. c. of 20:1 pyrethrum extract (the trade designation of a pyrethrumextract containing 2000 mg. of pyrethrins in 100 c. c. of extract); ismixed with 400 mg. of the methylene ether, 300 mg. ofbeta-chloro-beta-thymoxy-diethyl ether are added and this mixture isdilutedto 1.00 e. c. with petroleum base oil.

This example illustrates proportions and amounts suitable for making asmall amount of household spray suflicient for test purposes but largeramounts can be produced in a similar manner.

In the above example, the beta-chloro-betathymoxy diethyl ether is usedas a secondary solvent. Other secondary solvents such as those abovementioned may be similarly used.

The household spray produced in accordance with the above example ishighly effective against flying insects such as flies and mosquitoes.Sprays effective against roaches and other more diflicult insects can beproduced by appropriate variations in the proportions of the pyrethrinsand methylene ether, e. g. by raising the pyrethrin content from 20 mg.to mg. per c. c. of petroleum base oil and with a similar amount of themethylene ether to that used in the above example.

The new composition containing pyrethrins and the methylene ether can bemade in various forms including not only sprays but also insecticidalpowders or in the form of emulsions or suspensions in water or inconcentrated solutions to produce a surface paint or spray. The newcomposition may also be used in combination with other natural orinsecticidal materials.

Thus, insecticidal powders can be prepared, for example, by admixing themethylene ether with partially extracted ground pyrethrum flowers. Inthe manufacture of commercial pyrethrum extracts, the ground pyrethrumflowers which contain around 0.9 to 1.4% pyrethrins are extracted withsolvents such as petroleumhyclrocarbons. It is economical to extractthem only to the point where about 0.1% pyrethrins are still left in theflowers. Such partially extracted pyrethrum flowers may be dried andpowdered again to a particle size of about 200 mesh and used forcompounding with the methylene ether. Thus, for example, 1.0% of themethylene ether dissolved in a suitable solvent may be added to thedried powder and after thorough mixing a highly active insecticidalpowder is obtained which may be used on roaches, ants, silver fish andother household insect pests or which may be used as an agriculturalinsecticide.

An agricultural dust may also be prepared according to the followingexample.

A mixture of pyrethrum extract or pyrethrum oleo resin with themethylene ether (a suitable solvent such as isopropanol may be added) isthoroughly mixed with a carrier such as walnut shell flower to give adust concentrate containing 0.25% of pyrethrins and 2.5% of themethylene ether. This dust cencentrate when diluted with 4 parts of aninert material such as pyrophyllite will yield an agricultural dust ofoutstanding activity.

When the diluted dust is used to the extent of 20 to 35 pounds per acre(depending somewhat on the crop and conditions), it will control a widevariety of agricultural pests such as, Mexican bean beetle, leaf hoppersof various types, cabbage worms, celery leaf tiers, web worms, etc.

The new composition can be prepared in other forms such as emulsions orsuspensions in water or concentrated solutions can be produced and usedas a surface spray or paint.

The new composition can also be prepared for use in so-called aerosolbombs. An effective spray may thus be prepared containing 0.15% ofpyrethrins and 2% of the methylene ether in diOhIO-r rodifiuoromethane,a solvent that boils below room temperature. Such solutions when storedin a bomb and when the solution is released through fine nozzles to forma so-called aerosol spray give a spray comparable to a solutioncontaining 0.5% of pyrethrins without the methylene ether.

I an insecticidal powder, the active insecticidal ingredients of saidcomposition comprising pyrethrins and as a synergist therefor, ,themethylene ether of 3,4-oxymethylene-phenyl-l-butylglycol.

4. An insecticidal composition in the form of an aqueous suspension, theactive insecticidal ingredients of said composition comprisingpyrethrins and as a synergist therefor, the methylene ether of3,4-oxymethylene-phenyl-l-butylglycol.

. HERMAN WACI-IS.

REFERENCES CITED The following references are of record in the file ofthis patent or the original patent:

UNITED STATES PATENTS Number Name Date 1,990,422 White Feb. 5, 1935OTHER REFERENCES Soap and Sanitary Chemicals, January 1943, pages and96, by Roarck.

Chemische Weekblad, vol. 16, pages 1072-3, 1523-4 (1919), Prins.

Beilstein, vol. 19, 1934 edition, pages 84 and 85.

